Caps for cervix uteri as birth control devices are well known and have been found among the artifacts of antiquity. It has been reported that Aetius of Amida suggested for this purpose the use of the skin of a pomegranate cut into a hollow cup and that beeswax discs fashioned to fit over the cervix have been used in Europe.
Conventional cervical caps are made in many sizes to accommodate the various cervix sizes normally encountered, however, with such caps the fit for a particular individual is usually inexact and probably a compromise. Usually the cervix is either wedged into the cap or a compressive retainer or clamp is utilized. As a result, conventional caps often become dislodged during normal body movement, and particularly during coitus, and have to be removed periodically to accommodate normal uterine discharges.
Typifying the many types of cervical caps that have been developed are those shown in U.S. Pat. Nos. 2,836,177, 3,952,737 and 4,007,249, and German Patent No. 475,496 as well as in Das Weibliche Gebar-Unvermogen by F. A. Wilde in Berlin in 1838 according to U.S. Pat. No. 4,007,249. These cervical caps have met with varying degrees of success. In particular, the cap shown in U.S. Pat. No. 4,007,249 is made while the wall of the vagina is expanded by means of a speculum. Such an expedient tends to deform the cervix and thus precludes a good fit between the cap and the cervix. Additionally, medical grade silicone rubber, the material of choice in said patent for making the cap is not readily wettable, thus surface tension cannot be relied upon to hold the cap properly in place on the cervix. In addition, some medical grade silicone rubbers are porous, and cervical mucous, uterine discharges and bacteria are likely to accumulate in the pores, thereby causing unpleasant odor, in addition to a risk of infection. In such instances, cervical caps may be usable only for limited time period, e.g., about 6-8 hours.
It is therefore desirable to provide an improved cervical cap with an inner wettable liner that is impermeable or non-porous, and which conforms to the cervix uteri of the female for whom the cap is made, so that the surface tension created by a layer of mucous between the inner wettable surface of the cap and the exterior of the cervix will hold the cap in place and prevent dislodgement during intercourse or customary physical activities.